Customize Query

Example

const results = await session
     // Query an index
    .query(BlogPost, BlogPosts_ByTag)
     // Provide a callback for the 'beforeQueryExecuted' event 
    .on("beforeQueryExecuted", query => {
        // Can modify query parameters
        query.skipDuplicateChecking = true;
        // Can apply any needed action, e.g. write to log/console
        console.log(`Query to be executed is: ${query.query}`);
    })
    .all();

class BlogPosts_ByTag extends AbstractJavaScriptIndexCreationTask {
    constructor() {
        super();

        this.map(BlogPost, b => {
            const result = [];

            b.tags.forEach(item => {
                result.push({
                    tag: item
                });
            });

            return result;

            // This fanout index outputs multiple index entries per each document,
            // (an index-entry per tag in from the tags list).            
            // The query can be customized to return the documents without the duplicates,
            // (see the query example in the first tab).  
        })
    }
}

class BlogPost {
    constructor() {
        this.id = null;
        this.title = null;
        this.body = null;
        this.tags = null;
    }
}

class TagResult {
    constructor() {
        this.tag = null;
    }
}

Syntax

on("beforeQueryExecuted", eventHandler);

Example

let queryDuration = 0;

const results = await session
    .query({ collection: "employees" })
     // Provide a callback for the 'afterQueryExecuted' event 
    .on("afterQueryExecuted", rawResult => {
        // Can access the raw query result
        queryDuration = rawResult.durationInMs
        // Can apply any needed action, e.g. write to log/console
        console.log(`${rawResult.lastQueryTime}`);
     })
    .all();

Syntax

on("afterQueryExecuted", eventHandler);

Example

const results = await session
    .query({ collection: "employees" })
    .whereEquals("firstName", "Robert")
     // Add a call to 'noCaching'
    .noCaching()
    .all();

Syntax

noCaching();

Example

const results = await session
    .query({ collection: "employees" })
    .whereEquals("firstName", "Robert")
    // Add a call to 'noTrcking'
    .noTracking()
    .all();

Syntax

noTracking();

Example

// The projection class: 
class EmployeeProjectedDetails {
    constructor() {
        this.fullName = null;
    }
}

// Define a query with a projection
const query = session
     // Query an index that has stored fields
    .query(Employee, Employee_ByFullName)
     // Use 'selectFields' to project the query results
     // Pass the requested projection behavior (3'rd param)
    .selectFields(["fullName"], EmployeeProjectedDetails, "FromDocumentOrThrow")
    .all();

// * Field 'fullName' is stored in the index.
//   However, the server will try to fetch the value from the document 
//   since the default behavior was modified to `FromDocumentOrThrow`.

// * An exception will be thrown -
//   since an 'Employee' document does not contain the property 'fullName'.
//   (based on the Northwind sample data).        

class Employee_ByFullName extends AbstractJavaScriptIndexCreationTask {
    constructor() {
        super();

        this.map(Employee, e => {
            return {
                fullName: e.firstName + " " + e.lastName
            }
        })

        // Store field 'fullName' in the index
        this.store("fullName", "Yes");
    }
}

Syntax

selectFields(properties, projectionClass, projectionBehavior);

• Default
  Retrieve values from the stored index fields when available.
  If fields are not stored then get values from the document,
  a field that is not found in the document is skipped.
• FromIndex
  Retrieve values from the stored index fields when available.
  A field that is not stored in the index is skipped.
• FromIndexOrThrow
  Retrieve values from the stored index fields when available.
  An exception is thrown if the index does not store the requested field.
• FromDocument
  Retrieve values directly from the documents store.
  A field that is not found in the document is skipped.
• FromDocumentOrThrow
  Retrieve values directly from the documents store.
  An exception is thrown if the document does not contain the requested field.

Example

const results = await session
    .query({ collection: "employees" })
    // Add a call to 'randomOrdering', can pass a seed
    .randomOrdering("123")
    .all();

Syntax

randomOrdering();
randomOrdering(seed);

Example

let timingsResults;

const results = await session.query({ collection: "Products" })
    .whereEquals("firstName", "Robert")
     // Call 'timings', pass a callback function
     // Output param 'timingsResults' will be filled with the timings details when query returns 
    .timings(t => timingsResults = t)
    .all();

Syntax

timings(timingsCallback)

Example

const results = await session.query({ collection: "Products" })
    .whereEquals("firstName", "Robert")
     // Call 'waitForNonStaleResults', 
     // Optionally, pass the time to wait. Default is 15 seconds.
    .waitForNonStaleResults(10_000)
    .all();

Syntax

waitForNonStaleResults();
waitForNonStaleResults(waitTimeout);